Numerical Analysis On Matching Between Internal And External Bypass And Fan Of Aero-engine

Under the requirements of fast development from aeronautic industry, the R&D periods of the aero-engine are obviously shorten, in order to reduce the costs related to scientific research and testing periods. In this paper, the method of CFD is utilized to analyze three-dimensional distributions of steady flow fields in fan, booster, and internal and external bypass. The behavior of velocity and pressure parameters related to aerodynamic loading and flow stability are discussed in details. Also, the numerical analysis results are to be provided designers with the valuable criteria for the blade aerodynamic optimization of compressor.Internal flow and aerodynamic performance of the fan, booster, and internal and external bypass of a turbofan engine are selected as the research direction in this paper. The simulation regions include the fan, booster stages, and the external bypass. It is shown that the performance parameters provided by simulation at the designed condition are consistent with the given ones on the whole, and that the distributions of aerodynamic parameters in the flow field are basically matched with the practical physical problems . It is also presented that the total pressure rise at every stage of the compressor is proper. It is certain significant that the numerical analysis results are referred to the qualitative reference for the design of the compressor.At the designed rotate speed, when the outlet static pressure is reduced to some extent, the blockage occurred. When this happened, back flows were seen at the top of the core compressor's fourth rotor on the pressure side near the leading edge. Comparing the parameters at blockage with the ones at normal condition, it can be found that the absolute values of flow angle near the leading edge of every blade row are bigger when blockage occurred, which can lead to separations on pressure side.At the designed rotate speed, when the outlet static pressure is increased to some extent, the rotating stall occurred. Near the rotating stall condition, back flows were seen at the top of the core compressor's second stator on the suction side near the trailing edge. Comparing the flow field at the condition near the rotating stall and that of normal, the absolute values of flow angle near the leading edge of every blade row are smaller at the condition near the rotating stall, which can lead to pricking up of separation on the suction side, it is the main reason for stall cell's emergence.The result of simulation on the core compressor is compared between two different inlet conditions: inlet flow angle normal to the boundary and abnormal. The inlet flow angle at the latter condition was defined according to the result of the whole configuration's simulation. It was found that the two inlet conditions can neither lead to a perfect performance parameter, but the latter instance is a little better. From these,...